The role of the microtubule-associated P10 protein of baculoviruses is not yet understood. P10 has previously been linked with the formation of a number of cytoskeletal-like or cytoskeleton-associated structures in the nucleus and cytoplasm, thought to be involved in the morphogenesis of virus polyhedral occlusion bodies. The formation of these structures was studied by immunofluorescence laser scanning confocal microscopy in TN368 cells, a model system amenable to the study of virus interaction with the host cell cytoskeleton. We show that the Autographa californica nucleopolyhedrovirus P10 protein forms two distinct cytoskeletal-like structures, microtubule-associated filaments and perinuclear tubular aggregates. P10 also associates with polyhedral occlusion bodies. Depolymerisation of the microtubule network with colchicine prevents formation of P10 filaments but not of P10 tubules. Colchicine treatment enhances the association of P10 with occlusion bodies. Transient expression of P10 showed that both filaments and tubules can form in the absence of other viral proteins. We postulate a number of possible roles of the P10 protein during virus infection and morphogenesis.